The Court of Appeal does not consider the rental by the property developer a use of the office building that falls within the concept of going concern.
The property developer has developed the office building with the purpose to sell, not to exploit the building itself.
To the property developer, the transfer of the office building simply constituted the VAT-taxable supply of a new property, from its inventory of developed properties (the VAT group had even more developed properties that had not yet been supplied). The rental by the property developer is irrelevant in that respect now that the conclusion of the rental agreement was intended to make the office building more attractive for the sale, not by exploiting it itself.
Source: Deloitte
